The present invention is directed to integrated circuits and methods thereof.
In data communication systems, analog and digital signals are both used. Typically, digitized signals are transferred as analog signals through communication medium (e.g., modulated electrical signal through copper wires, modulated optical signal through optical links, etc.). As a part of communication process, signals are converted between digital and analog forms. Comparators are an important aspect of signal processing and performing analog to digital conversion. For example, to perform analog-to-digital conversion (ADC), comparators are important part of the conversion process. In a direct-conversion ADC process, a bank of comparators is used to sample the input signal in parallel. A successive-approximation ADC uses a comparator to successively narrow a range that contains the input voltage. In both implementations, the accuracy of comparators is important, as it directly contributes to the accuracy of the ADCs. To keep comparators accurate, it is needed to calibrate the comparators.
There have been various solutions and techniques for calibrating comparators. Unfortunately, these solutions and techniques have been inadequate for the reasons below. Therefore, new and improved systems and methods for comparator calibration are desired.